RichardE. Hughes,Geochemca Besearch Laboratory. 9991 Rver 1,4st Way RanchoCordova Caiforn a 956703180

TraceElement Geochemistry of VolcanicGlass from the ObsidianCliffs Flow,Three Sisters Wilderness,

Abstract ,l.hissnrhrrtsundertrkentoinrenig!|.lnnl.n|ia|in|t.v)UR'.trai'.]dnen

X jtdemess. Oregon. Gcr 1]rrl.tnrl80rlllhcscttr'nrlarh|rolleight1ocations fnl'cnLr!tnlnabu|dand'sofelerennlinor.trace.u shl8lhJtall1lx]!l]srepresentobsirlialofthesane((]hsirlian(j|ill)gllll of esuiblisling a geochernnal data b6e agonrsl $hi(h urrifucrs fton, Otgorr anlacol,gical sites can be conipared. lntroduction geochcnicul hrundation musl be established. grounded in analvsesreported in intclnational)y L,ntil cluite lecently. obsklian studies have attractecl rccognized measurement units calibrated to inter- little interest flom f)rcgon archacologists. Conse- nationalrock standards.It is only through adher quentlv. studies in the state havc luggcd bchind ence 1o analyticallv rifiorous standar-ds lhal tiroscconducicd in Calilornia uhere. iirr the last rcscarchcrs can begin to build a quantitatile data t\!o decades. archaeologistshavc rcapcd the base lor Oregon that can bc sharcd b,v benelit-. from thc partncrship ftrrged rvith geo- re!ellrcher'!.rl JiIit rt nt lrl,,'"rlofici. chcmists. There archaeoiogistshave emploved vol- canic glass studics to in!esligate (among other Rer:ognizingthis, the ultimatc goal of what has " topic-s)dilierences in prehistoric social ranking. corne lo be called sourcing" rescarch prehistorit'Lradeand exchange,ancl thc proclrrc- shoulclscnc trvo crrmplementarypufposes- the ftst tion hjstoricsof obsiclianquarries. Despite this lag. principall,v geor&.emicrzl,thc sccond principall,v ar- the archaeologicalpotential lbr C)rcgonobsidian thaeolo6gcal.Fi-st it rs necessaryto collect and ana- studiesis trul,vcxciling. sincc the state probabll lyze volcanic gla,ssesand to dctcrminc r\,hethel an]' c()ntainsas rnilnv artif:rct-qualitvsources of r.olcanic gcu,ll mi, .rl , r iJ, n, . -,, i.t. fnr irrtrosourcer ari.r' glassas arc knorvnlrorn anv regionof similar size Lilit,v among quarries. Havinpl accomplishcd thc in Lheworld. first strp, these baseJine geochemical data can be ernplo,vedto inrcst;gatc archacological qucsLions Hc,lever. belore the bencfits of obsirlian "lingerprinting" regarding the long term use-lifc history of obsid- studics(in this casc.geochernical ian quarrics,prchistoric tlacle and enchange.and or "sourcing")can be accruedarchacologically, it mobility patterns. The research reportcd hcrc t'us is first necessarr to locatc and geochemicall-v undefiaken to inrcstigatc only the firsLoI these t\vo characlerizepar-ent geologic soulces (and sourcc "proh1es." tvpes).since it is to thc gcochcrnical or "fingerprints." of thesevolcanic glasscs that rnea- The Problems surementson archaeologicalartilacts till be com- paretl. Despitethc initial skcpticismfor obsidi:rn The present studv is not thc first (scc Willians studicslhat hrlloweddisclosure of mistakesin both [94.X] for a geologicdescription ol the florJ to x-r:ry analvtical techniques and statistical tlassifi- generate trace element data for Obsidian Cliffs vol- cationsof obsitliarrsorrrccs ancl aftifacls through- canic glassbut. comparedto the geochernicaland oul Oregon (Sappington I98la,b; Tocpcl and archaeomelric attention deloted to the nearbv Sapping'ronl9{12; see Hughes 1984). subsequent Ncnbcrry (e.g. Laidlel' and NIcKayI971: studies(c.g. Hughcs l9B6a. b; Sknner 198i3)hale Higgins 1973: Fricdman 1977; Macleocl ancl realizedsome ol thc potcntid of such work. and Sherrod I9BB). researchon thc ClilTsis considcr- h.rr.cchartcd sornepronrising research directions. abh lcsscxlcnsive and detailed.Despite the work But belbre anv conlidence can be placcd in or- conducted ltl date. three problems remained which thacological ap1)iL:ationsof olisidian studies a solid requircd furthcr r-csearch.First. geochcmical

NorLhwesLScience, Vol. 67, No. 3, 1993 199

le 199:l l,\ lhc \odhrell S, ienriii,' Asrri.rli,''. All 'iglt' rtlrr\rd mcasurernentson obsiclianfrom thc Clilii (r\nLto- serrcd rt 1 l l2 localities.lhe intcnsitvofsuch ac- nen 1972; S. Tlughcs1983; -qkinner191313) remain tivitics (bascd on .lualitalive imJrrcssionsof the unpublishecland thc lcsults have not been l idcl-v :rmount of quarrv-t'orkshop deblis on thc surface) di-.seminaLr:d.Scurnd. Obsidian (ilifl'-sgla-

200 lTughcs /-- iX |

Figure L Aerial lieir ro sorrth,ast acn,ss Lhr: Ohsirlirn Ulills llo\L (lo$ef leli in phoro). with Colier Cone and th.i \,)fLh Sin.r if bockground. Arron speciliesthe reiririui ol tht llo{. shn,l, ,orhi)onds $irh ollection locarion i106 o! Fisur. 2.

using r 0.127 mnr Ilh primarr beam lilter in an elemenLintensilics \rcrc con\.cr1cdto concentration air path at 200 scconclslivctimc to fienerate )i-rav estimatesbl elnplovinga lcast-squarcscalibration intensitv dala lor elemr:nts Zn (Ko). Gt (Kcv.|.llb line establishecllbl each element lrom analvsis o{ (KoJ. Sr'(Ka). Y (Ko). Zr (Krr). and Nb (Ka). Ti up to 25 intcrnational rocl sl:rndards ceflified bv (K(1). Nln (Kcr). dnd total iron (!'ezo.r) inlensities the l.S. GcologicalSuncy. thc L.S. NationalIn- rrere gener:rtedbr opefaling lhe \-fav tLrbcaL 15.0 stitutc of Standards :rnd Technolopy. the Ceologi- k\. O.il0 rnA. tith a 0.127 rnrnulurninum (All lil- cal Sunev ofJapan. and the Centrc dc Rcchcrchcs lcr in an air path.rt 200 secondslivetime. r,hile Petrlgraphiqucs ct Ct'ochinriques(l'rance). !'urtlrer Ba (Kcrl intensities rlefe generalcd b! opcratin€rthc detailspertaining to r-ral tube operaling conditions, r-rrv tube at 50.0 kV. 0.35 mA. *iLh a O.6iJmrrr calibration dnd clcmcnt-specilic delec{ion limits al)- 'lrace copper (CLr)filtcr at 300 srconds li\.etime. pear in Hughes(l9tl{:}a). Thc r-rav analvseslere

Volcanic Glass frorr thc Obsidian Clilli !'lol. Oregon 2OI R.8E.

T.t5 S. T.t6 S. _(o

I

n o

l':,i"t A\ t:"",srsrER = ) ) oJMil"" o----'----1 Kilometers

\lmbersaround lisurc2.- Tl,,st.re oi (rregorr(tnnudrotrrr'glhflocariono{llrcsturlrareajrLheCa*adeRange * (sceTalrlc lr' i,i,',,1i.,,,i.titr" ,t"'," Lr,".r'= i""' rliich geologi srmplesifrc collflted

Hughes TABL[1.Truce.|arc|allandscktlrt]nlinorelenlentconlenlso|lo1cani('glasS.rlJ1ttedfromeightaretsat()bsirliarrCilis lse{ IrigL,r.2 lirr lu.athrst. A1l elementalrllues in prrrs |i,r tr,ilLi,',-cr.cpr iron (Fe). expfessedas roreliron {li)Or'l in wcight perrert. I = sanple nrern: S.D. : s!rir,li stan(la.ddeliatn,n; CVrl0 = (oefficie.r ol rariation. Tcrr sprtiruts ana\zed from each site. Sire numl).rs assignrtl br \\illamette National Foresr p.Jso..cl.

Collialion l.o.ali,trF

??5 t'17 7;8 142 7106 7t:la) ;t l3

ti \ 59; 60,1. 596 616 5il6 (t2 t- 615 612 s.D. :17 ul 22 52 3? 24 3a) ;:J tl 1 6

\IN 3lll :l[]3 3Ur 378 3B2 :]?8 3i1.1 3rx) s.t). t2 85 7 r); 27 2 22

'.,.7 i 1.20 t.22 L22 1.20 I,2I Lt9 I _21 1.21 s.1i. .03 .0J .03 .o2 .03 .01 .03 2 2 I I 2 1

- :t5 43 15 ,tj 12 15 S.D. 53 ,l 7 5 c\'0i, I:J |6l:l ]l

t7 IB l8 ti t6 s.l). 2 3 I 2 I il 11 l? ? 6 12 t8 t6

Rb /-6 16 i8 i6 75 7iJ 11 75 s.t). 2 .1 3 2 2 3 2 :l 1 2

X t0l 102 102 r03 102 102 t\)2 106 S.D. 1 3 5 I c\ab 1 2 :l 5 .1 6

\ x IB Iu IB lIJ l; t; IB S.D 1 I I l I I I I c\ !1, '1 :l 6 B

/,r - lJll B5 88 u; BB ll!) 92 S.D. 2 2 il 5 5 IJ :) .> C\'0/o I 2 3 5

\b - 8 B 9 S,D. 2 2 2 2 2 u 2:l 2a 2:l 33 2:J 30 32

Ba {J77 il,t5 899 n2r u66 a21 B:;I B9; S.D. iJJ 2:\ 3.1 2n 2l 36 15 2.) { 3 ,l t;

crrnpletell non destnlctivcl cortcr-free obsiclian Examination of sample means and stanclard devi- llakes and chunks \{ere clctachccl from geologir: ations reveals that all cight sites contain obsidian semplesand each n'aslinstld in distilled rvaterto of lemarkablv unilbrm gcochcmicalcomlxrsition: fpmu\. Jn\ 1'^sil,1.-rrrf.r, e ,,'nlrnrirrrtrl-. in fact, mean valucs for ull cight of the best nleas- ured elementso\.erlap at t$o sigma. Thus. there LaboratoryAnalysis: Results is sound jusLification1br concluding that thcsc cight Tracc clcmcnt valLresgenerated lbr B0 samplcs loc:ltionsleprcscnl cxposuresof obsidian of the from cight sarnplinglocations appear in Tablc 1. same geochemicaltvpe. Thc valucs in Table I also

Volcanic Cllss from the Ohsidian Oliff-sI'lon, Oregon 203 are in verv closc a€gccmcntrrith those generaled Discussion on a srnall numbcr of Obsidian (iliIIi samples b,r SLinner(1983: Appen(lixX)" illustratingthat non ,{lthough quantitatir'c mcasurcments (values destruciivequanlilatir'e EDXRF prolidcs conccn- feported in parts pcr million [ppm] and teight per- tration estirnatescongruenl \fiLh those generaled cent [0/o]composition) ar-ereported hcr-cfor cleven using thc clestmctiveVD\Rl' technique. minor. tlacc and rale elements.nut all ele- 'l'he menls are eqLrallvuscful in obsidiancharactedza- presentstudr pareallvrxpands thc numbcr tion studies. The besl elcmcnts to cmplov lbr ol minor. trace and rare earlh clcmcnt mtasurc- intcr'-source discrimination ale those J term ''di- ments 1br Obsiclian Cliffs glass (irorn fivc in Skin- agnostic" (scc also Hughcs 1990)- those minc,r. ncr's studvto elevenin Table I herein).anrJ thrse trace, and/or rare earth elemenls that arc wcll- additional clonents rdll likelv be of assistance in measuredbv x-rav fluorcscence.aDd $,hosecon- hclping to clistinguishbctncen Obsidian Cliflisgla-"s centrationsshow low variabilitv r.titlia a sourcc and and oLhcl obsidiarrsthich have sirnilar llb. Sr. :rnd rnarkcci variabilitv tucrorssources. Diagnostic elc- Zr compositions(c.g. Tnrnan Crcck Cravels.Group 'l rnents arc lhosc lthosc concentration values allow B; -slinner 198i3). The tract clcmcnt clatain able one to draw the dearest gcochcmicaldistinctions I :xe quite differentflom artifact-qLralitlobsiclians betweensoulces. In practice. lhe actual ;dcntifi- from thc ncarb_v\ewberlv Volcano (see TabJe 2: caLionof a diagnosticclcmcnt and suitesol diag- ci. N{aclcorl and Shcrrod l'able l]) and [988: nostic clcmcnts is inlluenced not onlv b,v lith the polphvriticmicroresit'ular obsidians ofthc instrurnent sensitivity and analvtical techniquc -SouthSistcr in the Ca,.cade Range (NlacdonalcleL (e.g.. r-ral fluorcscencevs. ncuhon activation),but al 1992: Appcndir l. B'I0]. p.17{)). [,.pecimens b,vthe concenhationol a parLicularclcmcnt in a The geochrmical contlusts among sources are illu-q- source undcr stuclv, trateclin Figurc 3 Lrsirrga bivariateplot of Zr vs. Sr abundance.

T{BLE2. Trace rlurcnr gdnhiniistrr oisi\cf ol)sidiansin the ricinirr of rhe Newbern \rol.aro. Oregrrr. All rah,s in palrs per million (ppn). except iror (!e) .\t,hiss..l ds li.ror in $.ishr pi,Ranr; \- :-.u.pl" n,""n, S.D. = -.ahdc sta,;lanl d{liltion. C\ 0/o: coefficient oflariatnD (nr perert). l,i!,r st(r i,ri,ns $cr lndlvzed ILom erLchsource, excepr 1\lcKar Burre an: lJ).

Big 0hsidian Grmc Hut (one \orth Flor East LaLe Elemert llo\ tlBB-) ll89 ) (l9l ) {190 ) {192'l Nl.K!\ BuIk Quufrz l\'11n.

Tix 1350 l3fi5 tl t6 l35il 1.17; I165 .-)68 S.D. 52 53 6; ;0 ,t8 3t I 1 ; ; I 6 lfr X 589 -15:) ,166 141 1tr6 3B: 3?6 s.t). l2 t8 21 12 3 { 2 ; 3 I I

|f:rl" i 2.60 2.24 2.29 2.23 2.:l() 1.97 I _B,1 S.D, .05 .t)5 .05 .04 .03 '2 2 1 2 2

Rb- tt; 12,' 126 t29 126 125 130 S'I)' I 3 5 t; (lv0/o I 5 .1 .1 1

SrX 53 59 59 62 59 sl) 1 3 2 ilV'll, 5 6 5 I 3

\- 12 3B :J9 it7 JO 35 3B S'D' I 3 I 2 (lV'X, il 6 6 ; z,i :11!) 271_ 2.73 2t-I 273 195 t7B s.D. I 6 B :l I 2 2 { 2

204 Hughes thc ObsidianCliills case. -(r is a diugnosticelement since il occLlls in coilcentrationsconsider:rbi,v p obove detectionlirrits. it r.ariesmarkedlv across Big Obsidian Flow sourcs. and coeilicientsof r,ariation(scc Hughes l9B.l) 1brall ObsidianCliffs collectionsites shor,; thal it is nrcasurcclr,".ith precision. On thc basi-rol lneasuremert prccision (as rnonilor-eclbv CVlo lalues;'l'able I). Ti. Newberryvorcano NIn, Fe,,O.L,Rb. Y. Zr and t Ba also could be ct)nsiderrddiagnostic eiements. Zn. Ga and \b ppm concentr-ationsalso r,".ere mcasurecl and reported for cach collection Lrca- E McKay Butie tior. but thcsc clcmentsare not consirlcrcdcliag- South Sistcr nostic becausethe;- do not go. 200 I usulllv valv significantlv acnrssobsiclian sources (see Hughcs l982. 198.1. N I l986b). and bccausecoeflicienLs of rariution for Quartz Mountanl these thfee elementsitrc ntuch lafger Lhanlhosc of thc rem:rinirrgeighL. Although Zn, Ca and Nb were noL diagnosti(:clcments in this pa|ticular studv.cach clcmenthas to be evaluatcdon a ca-(e, 6 br-casc basis since it i-qdear that volcanic glasses ocr:ur in wirich somc ol drese(e.g.. Nb irr ccrtain Obsidian Tclaho[Nelson 198,,tr:Tablc 5. source #l3B],-{ri- zona [Jack 1971:Table l] ancl Ncrl Nlexico [Hughe-s19BBb] rfisidiansi and other elernenls (e.g..Sn in ccnain Peruvi:rnobsidian IMacdonald 0 100 200 300 ct al. 1992: Appendi-r1. specimcn1601) can sene Sr (pprn) in a diagnosLic cap:rcitv.

Figure :J. Bnariari, t,lorol Zr rs. Sr ahurdakcs ir lirc rrapr ( ascrde Itrnge ol,srlin,, s,,!Rc ichemicrl) t\tes. Conclusions Plols me,lc lronr rr\r data srrnDarizll in Trb 'l'here es 2 ar-esrrcral pointsthat shoulcibe nraclcwith und i3 hereiri. crceq,L S0urh Sisrcr {dNtr from l'h.- regard donrl,l.trl. l(r92:^pperdir 1.1,.l2B.srrri,fcns to these geochernicalfindings.'Io the ex- 8 l0l. qrer squares Fl,r1.s.nt obsi,lid Irom rhe Bis tent that this unifirrrr minor. trace and rarc c;rrth Obsicliarrllor. \r.wbcrrr \ olcano: filled triarglc" element profilc moniton underlr-ing geocncmrcd rrpr r:*:rt li,rr rurce locaLiiier(Canr Hur- P!micc homogcneity,it should rrot bc possibleto pursue Cone. \orth. and Last l-ak llovs) ir the Nenbern oh-idianlrr,llrtiLrn strrJi,. to .rddr---,trr--ti,,rrs \ ol.u,,; l; .,1 {rrures fepresent lI.Kr\ BL,Lt(ii,)r! f ltlating to the use-liie historv of thc Obsidian (lliills circles Quartz \lounLairr anrJopor triunglesdepirt -sourcesincc Ohsdi!,i Clills obs ian. South -qisi.r r!)rr)hrriri( thc probrbilitv ol irrtrasourccheter- nrlcfo\esicular,,bsidia,,is nlrsenteil on the dia ogcncitvol sulficienLmagnitLrclc to ailect obsidiarr gran l,r r s'rrbols. hvdration ralc dcvclopmentnon' appearscrcccd- ingh Jishl. \lrri,,r'..'r'drnin"r -l-rncnt luml'u-itiorr For e-rarnple.Sr is in rnostc:rses an e\tferncll data to -cupporlthis contlLrsionappear in Skinrrer uselul tlace element in obsidian sourcingstudies (1983: Alrpendir !ll. l'able\rII- L). Likewisc"thc bccause it c:rn be rneasLrrcdl,".ith good precision gcochemical uniformilv across all toolstone

\olcanic Olass fron thc Obsidian OJiffsFlor. Orcgon 2O5 liom sourccsto the east of the Cascaclcssince it Acknowledgements 'locallv" coLrldn'tbe obLrined (i.c., at Obsidian The ficlclrr.orkand laboratorr analvses lere sup- (llifi. ,,r in it- d.riv J rirel grrr-i-r. portcdbv the W-illametteNational l orestunrlcr the Finallv. bevond thcir irnmediaLrgcochemical terms of U.S.D.,{. purchase orrJcr no. utiJitv of contributing L(rLhc cstablishment of a com- 40-04.R4-7-?t 28. Thc ficld collectionphase *as completed in prehensirc rnulti-elelncntregional tJatabase lor Septcmber. L9ti7" bv the auLhor.Car.l f)aris. Silvermoon, )'lar.L Su,ift Oregon obsidians to rvhich archaeologic. a ifads Jon ancl llichellc Ilonahue. Carl D:rvis. \\'illamctte \ationai Forest (an bc compared. thcse geochernic{ldat:r prorn- -A.r'chacolo$st.r,ras largcl,v responsiblc for planning ise to bc pirotai in subsequerrtarchaeological and implemerrtingthe project. His organ;zational studies:in particularthosc concerned lith recon- -Ul-. a,lmirri-trntir'Fli,rlr JnLl |ari, n,e eorr- stmcting svnchronic and diachronic asperts oI pre lr'ihutedsignilicantlv to the overallsuccess of the hisloric prot'urcmcrlt and c()nr.cvaDcesvsLcms project. The AnthropoiogicalStudies Centcr and (tradc and exchangc).studies focusing on charrgc the Sonomn Stateflnivcrsih Academic Foundarion. and stabilitvin prchistor.icserrlcrncnt subsislencc Tnc. aiso Jrrovided support during the ficldt'orl.i svslens and population rnobilitv. ancl research phasr of the project. I thank Tammara Ekness- direr,terltoward identili,ing funcLionaland temporal Hovle ibl drafting Figure 2. Jennifer Collins Ibr valiabilitv in the obsidian tool producrion histon' pr"parir'yT.rhle 2. arll \,,,.r/rap.r5, ierr,. rnr ier^-r- oi thc 0bsiclian Clil1s. fr-,r constructive ()mmcnts on lhe manuscrift.

LiteratureCited Hugh.s- S. S. 1983. I'jetlo,Lcnrif d erolurirrrrn l ligh Cascad| lol.uic ro.ks tlrr'lhrce Sisterc R,is;,n,. Oregon. Or.- {nrronen. C. J. I972. Irece elemehrsin r},, lligh Can!d. rol go,, Sllle Lni!ers;L!. Con! is. I,h.l)_ DisseftatnD. canii rrrks. Three Sistcrs areo. Oregor. Srrnforil JocL-F. N. I97 L. The lrunri ,)l obsiilianadiia rs iD north.n, t riv.rsirv. Ph.D. l)is*rr!rion. Arizorru- l'luteru .1il: 103-l 1.1. FiedDran. L l.li7. H\dra ,n rlrting o{rolcarls ar Newbenr -- 1976. Lrhisroric obsnlirr in Cal,iJonnat: s,uhem r:,,r-r.ur,j. , t .-. " . . -u r. J. H,-. ,.JJ; {t2. l.!l ospe.rs.,, R.E. Tallor {.d.). ldruces ni Obsid a;rilf . l. B . ]| A Conl,rs. rnd lJ. A. \{ rishr. li)69. Identifi- i,n [:hss Studnis: Archaeolosical !n,l Ceocheornal cdrion o1 thf itrces of Hof.$.liri obsidian i,, rh. tl.rspecrtues. \o\,\ Pfess. Pdl RnlKi. \e$ Jerse\. t1,. tr'lrldl, $.ir. .\mer. Anriq!il' u.1: L r.!. 183217. Higg;b. \l \{. 1973. ll,rr,hg' ol \erb,i'.\ lolcano. {lni- Ja.L.R. \.. lnd LS.r. (lrrmi.hael.1969. The chen,nal lin gon. Bnll. ()rr,l. So.. ADer. B:[: 15; .11]8. K fpdntny ola. r,,lclnic ro.Ls. Cllill Dir. X'liiesal llughes. Il. E. I'182. Ase ard r:xpl,,jrurionof obsnlia,, 1rcm (;r,1. Spec.Rept. 100: l7 32. the \lrrln,ine Lake Hlg|lanrl. Colifornia.J. Archaeol. '1h,i JlcksoD-1. L. l!l;4. r(r,,,omicof obsnlianjn S,;. q: lTll l il;. cennal Callorrriu appli,aLions of1 ra\ ,,,r,tr srence . {18-1.Obsidi!,, {rrciDs stuiin's;, rh..Crert Ba- lrrchiston: spechr,grap|rir rrchaeol,gv.Dcpu nreDroiAnrhfo sin: pfobleDrs a,,d r,fo\rNrs.1a Itn:har1 li. llughes (ed.J pologr'.San l..rnciscoStare t.,,;v{.rsirr. Obsiclian StLrlirs in the Creat Uesir. Cortrib.Lnir. Calil. M.A. lhcsis. L!i(ll.!. .{r.h!d, . R{s. Fa.il.lr;: l -li:). R. A.. an.tt). s. ItcKar. 1971.Geochernirat crrmi nation ofobsidians . lL)86r. E!.fi.\ rlispersire r rar fluoucence anar- lrom the \(\Ltrf.n Cal.lerr. 0f. gon.(lorl|il,- Uinerrl. vsis of obs irr lfonrDogHill rn,l llurns Bun.. Oril Peri,l. 30: 3.163.12. go!. \,)rth$. Sci. 60: 73-80. \larrlonuld.R.. Ii. L. Srnith.and J. E. l loma.. 1992.Clrris . 1986b. Diachroni| variabilin n olsnlian procure rn ofrhesubalk! ic silici.ohsnliuns. U. -s.Ce(,1. Sur. Prol. nrJ,r l)ltternsitr northiia\lern C:Llilorrnaand soudrcentral I'aper 1523- r)..r,,rIr,i\.i.1,. p,t,t \r,rl,.,. t:. X'lacleod-\. S..end D.Il -qhcrr .19811(leol,gn eridence .lglllja. 1h. (i,so roLc.nic fi.].1 .,! \rnnred: impl; for a ,nqi,r{ chonb.r hdn,arh\e\rberr\ Vol(nno.Ore, cariors i.r,,bsi,lien sourcn)g!,xl hrdrruox ulurir r- gor. J. (;(!phrs Res.93: 10.06710,iJ79. -rea(h. ccodrfhaeol. :t: 253 263. \flson. F. \\J.Jr. r981. X rai n,,orscencearat\sis ot sone .l()iliih. Ar.ha(t,logicel signilicarrc ol geochenical testerr \orrh Amernlr ,$snlians. /, Richufd E. contra:ts an,rg southwe;terr \sr \Ierico obsidiars. Hughrs {ll.). ObsidianSLurlis in the Crar Brrsin.Cor Te\.is J. Scj. :10: 297':10i. hib. l,.iv. Culiil.{rchae,,l. R.s. Facil.15: 27 62. .19q0. Obsidian s,n,rf.s ar Jures Cii!.h,shflrer. :ud Srppingtor,R. l..lt)gla. A prog.,ss reporton rh(i,,bsidian tfa(. clenreDt"e,x licnisrn o{ yD. nonhcastern Ne, encl lirroth\r' sourcingpi).1.(it. lr]!ho ArL:Lacol.,1: rd(h rol.irnr slrsn.s. ,rn R. c. llsr(,f en(l E. tsudi .117. ,,,l-'. I hp \r, l' '.,.,,,r^ut |'1r--,:r,.|:i. lr"r lh . 19811.The arrhacobp ofrhe L\dk.Gulch sir,. L.rahADthro. Pnt,. ll5: 297-305. 110AA-?2)r rrehisto'n o(r ularioniD th. B,)jnjRiler ltrshes. R. L.. ,l f. tr. \etsoD.I98;. NeN liDdiiss on,,b (lani,r,. sourh$esterDl.laho. Lnir. Idah,) Rcs.IaDu- sirlian source utilizatior in loira. Plains Anrhro.32: itn Sc.. 66. 3trJ316.

206 Hughcs 'lir1c. Slinner. C. lgU:J. Obsidiar stLrdn'sni Orcg,n: an iiltnxl!,- K.A.. !n,l R. 1..Slppingron. l9il2. Obsidianuie nr tioD k obsidian erd an irrestigati.,i ofs.l.t1,{l nrith, s rlif Ilillnrelle \!lle!: rrLfeelemeDt anrhsi-. o{obsiil ofobsidiar characteization ut izng ol,sidiar co11er:tr1 ian l;on, th,.Halv.rson iirc. T.rbii{! l91 27,10. 11 pfehislofi! qurrn sites ni Oregor. Lnirersit! ofOre' \\ illiarns-H. 19,14.\ ol,ano.s 01d,. Tl,u SisrrrsresioD. Ore gon. firrglrr:. \1.A. Thrsis. gonCascade-.. thi!. Calif.llul,1. Crol. S( i. 27: 37-81.

Receied 20 llarch 1990 Au:epted lbr publitution I FeLnuan 1993

\olcanic (llass from the Obsidian Cliifs Flot. Oregon 207